/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.library.dprofile.util;

import org.apache.iotdb.commons.udf.utils.UDFDataTypeTransformer;
import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
import org.apache.iotdb.udf.api.access.Row;
import org.apache.iotdb.udf.api.exception.UDFInputSeriesDataTypeNotValidException;
import org.apache.iotdb.udf.api.type.Type;
import org.eclipse.collections.impl.list.mutable.primitive.DoubleArrayList;
import org.eclipse.collections.impl.list.mutable.primitive.FloatArrayList;
import org.eclipse.collections.impl.list.mutable.primitive.IntArrayList;
import org.eclipse.collections.impl.list.mutable.primitive.LongArrayList;

import java.io.IOException;
import java.util.NoSuchElementException;

/**
 * Util for computing median, MAD, percentile
 */
public class ExactOrderStatistics {

    private final TSDataType dataType;
    private FloatArrayList floatArrayList;
    private DoubleArrayList doubleArrayList;
    private IntArrayList intArrayList;
    private LongArrayList longArrayList;

    public ExactOrderStatistics(TSDataType type) throws UDFInputSeriesDataTypeNotValidException {
        this.dataType = type;
        switch (dataType) {
            case INT32:
                intArrayList = new IntArrayList();
                break;
            case INT64:
                longArrayList = new LongArrayList();
                break;
            case FLOAT:
                floatArrayList = new FloatArrayList();
                break;
            case DOUBLE:
                doubleArrayList = new DoubleArrayList();
                break;
            default:
                // This will not happen.
                throw new UDFInputSeriesDataTypeNotValidException(
                        0,
                        UDFDataTypeTransformer.transformToUDFDataType(dataType),
                        Type.INT32,
                        Type.INT64,
                        Type.FLOAT,
                        Type.DOUBLE);
        }
    }

    public void insert(Row row) throws UDFInputSeriesDataTypeNotValidException, IOException {
        switch (dataType) {
            case INT32:
                intArrayList.add(row.getInt(0));
                break;
            case INT64:
                longArrayList.add(row.getLong(0));
                break;
            case FLOAT:
                float vf = row.getFloat(0);
                if (Float.isFinite(vf)) {
                    floatArrayList.add(vf);
                }
                break;
            case DOUBLE:
                double vd = row.getDouble(0);
                if (Double.isFinite(vd)) {
                    doubleArrayList.add(vd);
                }
                break;
            default:
                // This will not happen.
                throw new UDFInputSeriesDataTypeNotValidException(
                        0,
                        UDFDataTypeTransformer.transformToUDFDataType(dataType),
                        Type.INT32,
                        Type.INT64,
                        Type.FLOAT,
                        Type.DOUBLE);
        }
    }

    public double getMedian() throws UDFInputSeriesDataTypeNotValidException {
        switch (dataType) {
            case INT32:
                return getMedian(intArrayList);
            case INT64:
                return getMedian(longArrayList);
            case FLOAT:
                return getMedian(floatArrayList);
            case DOUBLE:
                return getMedian(doubleArrayList);
            default:
                // This will not happen.
                throw new UDFInputSeriesDataTypeNotValidException(
                        0,
                        UDFDataTypeTransformer.transformToUDFDataType(dataType),
                        Type.INT32,
                        Type.INT64,
                        Type.FLOAT,
                        Type.DOUBLE);
        }
    }

    public double getMad() throws UDFInputSeriesDataTypeNotValidException {
        switch (dataType) {
            case INT32:
                return getMad(intArrayList);
            case INT64:
                return getMad(longArrayList);
            case FLOAT:
                return getMad(floatArrayList);
            case DOUBLE:
                return getMad(doubleArrayList);
            default:
                // This will not happen.
                throw new UDFInputSeriesDataTypeNotValidException(
                        0,
                        UDFDataTypeTransformer.transformToUDFDataType(dataType),
                        Type.INT32,
                        Type.INT64,
                        Type.FLOAT,
                        Type.DOUBLE);
        }
    }

    public String getPercentile(double phi) throws UDFInputSeriesDataTypeNotValidException {
        switch (dataType) {
            case INT32:
                return Integer.toString(getPercentile(intArrayList, phi));
            case INT64:
                return Long.toString(getPercentile(longArrayList, phi));
            case FLOAT:
                return Float.toString(getPercentile(floatArrayList, phi));
            case DOUBLE:
                return Double.toString(getPercentile(doubleArrayList, phi));
            default:
                // This will not happen.
                throw new UDFInputSeriesDataTypeNotValidException(
                        0,
                        UDFDataTypeTransformer.transformToUDFDataType(dataType),
                        Type.INT32,
                        Type.INT64,
                        Type.FLOAT,
                        Type.DOUBLE);
        }
    }

    public static double getMedian(FloatArrayList nums) {
        if (nums.isEmpty()) {
            throw new NoSuchElementException();
        } else {
            nums.sortThis();
            if (nums.size() % 2 == 0) {
                return ((nums.get(nums.size() / 2) + nums.get(nums.size() / 2 - 1)) / 2.0);
            } else {
                return nums.get((nums.size() - 1) / 2);
            }
        }
    }

    public static double getMad(FloatArrayList nums) {
        if (nums.isEmpty()) {
            throw new NoSuchElementException();
        } else {
            double median = getMedian(nums);
            DoubleArrayList dal = new DoubleArrayList();
            for (int i = 0; i < nums.size(); ++i) {
                dal.set(i, Math.abs(nums.get(i) - median));
            }
            return getMedian(dal);
        }
    }

    public static float getPercentile(FloatArrayList nums, double phi) {
        if (nums.isEmpty()) {
            throw new NoSuchElementException();
        } else {
            nums.sortThis();
            return nums.get((int) Math.ceil(nums.size() * phi));
        }
    }

    public static double getMedian(DoubleArrayList nums) {
        if (nums.isEmpty()) {
            throw new NoSuchElementException();
        } else {
            nums.sortThis();
            if (nums.size() % 2 == 0) {
                return (nums.get(nums.size() / 2) + nums.get(nums.size() / 2 - 1)) / 2.0;
            } else {
                return nums.get((nums.size() - 1) / 2);
            }
        }
    }

    public static double getMad(DoubleArrayList nums) {
        if (nums.isEmpty()) {
            throw new NoSuchElementException();
        } else {
            double median = getMedian(nums);
            DoubleArrayList dal = new DoubleArrayList();
            for (int i = 0; i < nums.size(); ++i) {
                dal.set(i, Math.abs(nums.get(i) - median));
            }
            return getMedian(dal);
        }
    }

    public static double getPercentile(DoubleArrayList nums, double phi) {
        if (nums.isEmpty()) {
            throw new NoSuchElementException();
        } else {
            nums.sortThis();
            return nums.get((int) Math.ceil(nums.size() * phi));
        }
    }

    public static double getMedian(IntArrayList nums) {
        if (nums.isEmpty()) {
            throw new NoSuchElementException();
        } else {
            nums.sortThis();
            if (nums.size() % 2 == 0) {
                return (nums.get(nums.size() / 2) + nums.get(nums.size() / 2 - 1)) / 2.0;
            } else {
                return nums.get((nums.size() - 1) / 2);
            }
        }
    }

    public static double getMad(IntArrayList nums) {
        if (nums.isEmpty()) {
            throw new NoSuchElementException();
        } else {
            double median = getMedian(nums);
            DoubleArrayList dal = new DoubleArrayList();
            for (int i = 0; i < nums.size(); ++i) {
                dal.set(i, Math.abs(nums.get(i) - median));
            }
            return getMedian(dal);
        }
    }

    public static int getPercentile(IntArrayList nums, double phi) {
        if (nums.isEmpty()) {
            throw new NoSuchElementException();
        } else {
            nums.sortThis();
            return nums.get((int) Math.ceil(nums.size() * phi));
        }
    }

    public static double getMedian(LongArrayList nums) {
        if (nums.isEmpty()) {
            throw new NoSuchElementException();
        } else {
            nums.sortThis();
            if (nums.size() % 2 == 0) {
                return (nums.get(nums.size() / 2) + nums.get(nums.size() / 2 - 1)) / 2.0;
            } else {
                return nums.get((nums.size() - 1) / 2);
            }
        }
    }

    public static double getMad(LongArrayList nums) {
        if (nums.isEmpty()) {
            throw new NoSuchElementException();
        } else {
            double median = getMedian(nums);
            DoubleArrayList dal = new DoubleArrayList();
            for (int i = 0; i < nums.size(); ++i) {
                dal.set(i, Math.abs(nums.get(i) - median));
            }
            return getMedian(dal);
        }
    }

    public static long getPercentile(LongArrayList nums, double phi) {
        if (nums.isEmpty()) {
            throw new NoSuchElementException();
        } else {
            nums.sortThis();
            return nums.get((int) Math.ceil(nums.size() * phi));
        }
    }
}
